94 sugar sands mirage jet boat with a merc 90 hp

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hypersniper

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not completely sure if im in the wrong forum but i know the merc 90 sport jet is pretty much just a force powerhead on a jet drive right ... ok well i was given a 94 sugar sands mirage jet boat and theres really not alot of info on the net about them and as i own a force 85 outboard i noticed alot of things were pretty much the same. that being said... can i take any 1994 mercury 90 hp powerhead and change the base plate to match up to my jet drive or were they made model specific for the jet boats ? i know theres a few things different but mine has a blown head gasket and the bottom piston and cylinder are pretty scored and seems to have a good amount of side play. the boat its self is literally in mint condition i mean like almost showroom condition. it gleems in the sun for a 94 and i know these are fun little boats. i just dont wanna buy a head gasket and slap it in and find that the bottom piston is really wasted bad and id rather not have to have it bored out. can it be resleeved ? top 2 pistons are in incredible shape as well as the cylinder bores.
http://i96.photobucket.com/albums/l173/fourhoofsfarm/IM002870.jpg
http://i96.photobucket.com/albums/l173/fourhoofsfarm/IM002866.jpg
http://i96.photobucket.com/albums/l173/fourhoofsfarm/IM002872.jpg
 

fucawi

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Re: 94 sugar sands mirage jet boat with a merc 90 hp

boring out would be more reliable than a re sleeve ...but only you have the micrometer in your hand ......boring one piston/bore is fine ..no need to do all three ....are you sure its the bore and not he piston that is the problem ..may only need a hone and a piston
 

hypersniper

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Re: 94 sugar sands mirage jet boat with a merc 90 hp

im not sure really what it need as of right now. i havent even split the block yet to pull the power head. do i have to pull the flywheel and magneto to split the block from the power head? i think the whole problem was caused by the head gasket going then sucked up some sand and it just wreaked havoc on the lower piston. real bummer cause like i said the boat is mint. guy had it in his storage and wanted to sell the trailer and just wanted to give the boat away so i drove and hour and a half with my trailer and we swapped it onto my trailer and i took it home and washed the dust off it and boom ... brand new boat. now im gonna sell my bowrider cause this will be more fun when i get it running. but anyways back to my original question just for poops and laughs will any 94 merc powerhead fit in it if i swap some parts over like the exhaust and such?
thanks again and fucawi... love the name ... where the fucawi indian tribe
 
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hypersniper

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Re: 94 sugar sands mirage jet boat with a merc 90 hp

ok pretty much got it all figured out . now i need to get some of the wiring figured out. does anybody have a wiring diagram for these ? i know ebay does so you all can hold onto that comment.
thanks
 

hypersniper

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Re: 94 sugar sands mirage jet boat with a merc 90 hp

well i just ran a compression test on the bottom cylinder and it was right above 120. the center is 150 as is the top so i guess im looking at the very least a new piston and ring for that lower. i managed to flip the old head gasket around to take the compression test on the lower cylinder just to test it out. time for a complete tear down i guess. still cant complain. the boat was free oh wait i paid $35.00 for gas to go get it ... still a nice little boat tho.
 

hypersniper

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Re: 94 sugar sands mirage jet boat with a merc 90 hp

ok well i did the complete tear down today... and wow was i surprised at what i found. took the power head off and it looked like a brand new motor inside. i mean spotless like it just came from the factory. took the bad piston out and the sleeve had a slight score in it but the piston was wiped out. im assuming the piston got the worst of the damage cause its a softer metal. a nice hone on the sleeve and a new piston/rings and head gasket and hopefully it will be like a brand new motor. i mean this thing sat for a year or so and there wasnt even any rust or a speck of rust or dirt in the engine. does anybody have the torque specs for this thing handy ? mains, case and head please. is there anything else i should be on the lookout for while i do a further inspection of this? i did a quick inspection and nothing really jumped out at me. im gonna get some pics of the inside so you all can see what i mean by spotless. there were quite a few good sized pebbles lodged in the water jacket and im assuming thats what caused it to overheat and blow the head gasket and then suck in a bunch of sand and reeked havoc on the piston. thats the only thing i can think of that might have destroyed this thing. seemed like there was plenty of oil getting into it with the exception of the bottom cylinder being washed clean by the bad head gasket... any help or any torque specs etc would be greatly appreciated. dont really have the cash to go and buy a manual right this second. im not even sure of the model number on this cause i cant read the lable. any way to tell what model it is by things being different etc ?
thanks all
 

barten111

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Hello folks I have a 94 with a 90hp merc in it. I checked compression on all and found out top cylinder was good at 125psi and 2 and 3 were 10psi and 0 on number 3. My questions are, is it worth rebuilding it or just replace it? My second question is, is there some specific way to remove the power head from it? Cause i cant get it out eventhough i removed the 8 nuts that i can see, please any help will be appreciated.
 
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